Aneuploids have been identified among progeny from the homozygous recessive asynaptic soybean (Glycine max (L.) Merr., 2n = 40) mutants T241 and T242. The majority of the progeny (206 of 217) examined were near the tetraploid level and were sterile. The only fertile F1aneuploid had 36 F2progeny, which ranged in chromosome number from 41 to 44. Among the F2progeny, pollen fertility, number of seed per plant, and plant height decreased as chromosome number increased. No morphological differences were observed among the F2trisomics or between them and fertile diploids. The progeny of 2 of 3 F2trisomic plants contained plants with 42 chromosomes, suggesting simultaneous transmission of the extra chromosome in both the pollen and the egg.